The idea of using an inflatable balloon as a device for signaling the location of a person in distress has been known at least since the beginning of the present century. An example of an early proposed device is disclosed in U.S. Pat. No. 827,350, granted July 31, 1906, to A. C. Crofford. In the Crofford device, a signal balloon is attached to a life preserver to signal to passing boats that a person is in the water and is in need of rescue. With the advent of aircraft and their use in search and rescue missions, the interest in location signal balloons increased. Their use in various environments has been proposed, including open water and remote mountainous and/or forested areas.
A number of problems have been encountered in association with known proposals for signal balloons. A major drawback of previously proposed balloons is that their configuration, which is usually substantially spherical, causes them to have a tendency to drift downwind and downward in the wind. The resulting loss in altitude decreases the effectiveness of the balloon by decreasing the distance from which it is visible. The downwind drifting also makes it more difficult to accurately pinpoint the location of the person in distress. In forested areas, the decrease in altitude can even cause a balloon to descend below tree top level and thereby become totally ineffective. Another problem with known signal balloon apparatus is that it is often heavy and unwieldy. In some of the proposed systems, components like transmitters and power sources are carried into the air by the balloon. The added weight of these components makes it necessary to make the balloon larger to provide the required lift. The larger balloon in turn requires a larger housing for the balloon and a much greater capacity for generating or supplying lighter than air gas to inflate the balloon. In summary, although the concept of a signal balloon has been known for several decades, there is still an unmet need for such a balloon that maintains its effectiveness regardless of wind conditions and that is sufficiently light and compact to be carried by an individual, such as a hiker, in relatively remote areas.
U.S. Pat. No. 3,002,490, granted Oct. 3, 1961, to M. F. Murray, discloses a survival kit which includes an inflatable brightly colored spherical balloon. A flag is attached to the tether below the balloon. Murray states that the round balloon has a tendency to drift downward below the tree tops on windy days and that, therefore, his balloon is constructed along the lines of a kite with a string attached to the center of the same so that it climbs if the wind is blowing. The manner in which the balloon and flag structure that is shown and described functions to produce this result is not clear.
U.S. Pat. No. 3,279,419, granted Oct. 18, 1966, to M. A. Demarco discloses several embodiments of a spherical signal balloon. One embodiment includes fin-like external ribs each of which extends along the surface of the balloon in a semicircular vertical arc. The ribs are described as causing the balloon to rotate in a horizontal wind. In another embodiment, the ribs are twisted rather than being in a straight vertical arc. These ribs are described as providing additional lift force to the balloon from horizontal winds which strike on the underside of the ribs.
U.S. Pat. No. 3,727,229, granted Apr. 10, 1973, to B. W. Clinger et al., discloses a spherical signal balloon having a conductive tether which is either a single wire conductor or a thinner wire twisted with nylon filament for strength. The conductive tether is connected to a radio freqency transmitter on the ground to provide radio frequency energy to the balloon to cause the balloon to luminesce. The tether may also act as an antenna for the transmitter. One embodiment of the balloon includes an upper hemisphere with a metallic coating and a lower hemisphere with a phosphor coating. In another embodiment, the western hemisphere is provided with a metallic coating. An additional embodiment of the balloon is shown in a folded condition and is described as being cylindrical and as being capable of being folded in a vertical column of predetermined length, width, and height.
U.S. Pat. Nos. 4,123,987, granted Nov. 7, 1978, to R. C. Singerle et al.; 4,185,582, granted Jan. 29, 1980, to C. C. Bryant; and 4,219,819, granted Aug. 26, 1980, to R. M. Patel, each disclose a system which includes an antenna for a radio transmitter. In the Patel and Bryant systems, the antenna is a metallic tether connected to a transmitter on the ground. In the Singerle et al. system, the transmitter is carried into the air by the balloon, and the antenna is a metallic material tail attached to the base of the balloon. Patel also discloses the simultaneous opening of the casing for the apparatus and the valve mechanism for inflating the balloon. A relector is hinged to the casing, and a switch that is activated by the reflector hinge activates the transmitter.
U.S. Pat. No. 4,114,561, granted Sept. 19, 1978, to V. F. Asaro, discloses a system in which an insertion needle extends through a lip on the balloon filler nozzle when the balloon is stowed. Following inflation of the balloon, the needle is withdrawn and the self-sealing lip closes to seal the inflation orifice. The mechanism is activated by pulling a lanyard which is attached to a cam lever. The pivoting of the cam lever moves a gas container end seal against a puncture needle.
A signal light carried by a balloon is disclosed in U.S. Pat. Nos. 2,619,303, granted Nov. 25, 1952, to H. M. Martin; 4,048,565, granted Sept. 13, 1977, to L. E. Rice, Sr.; 4,178,867, granted Dec. 18, 1979, to J. Y. Shyu; and 4,416,433, granted Nov. 22, 1983, to J. H. Bellina. In the Rice, Sr. and Bellina systems, an intermittent or strobe light is carried on the tether below the balloon. In the Martin and Shyu systems, the light is positioned inside a translucent or semitransparent balloon.
The patents discussed above and the prior art that is discussed and/or cited therein should be studied for the purpose of putting the present invention into proper perspective relative to the prior art.